CVE-2025-39793: high-severity vulnerability in Linux
io_uring/memmap: cast nr_pages to size_t before shifting
Published · Updated
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.8epss 0.2%
exploitation probability
0.2%top 95% of all CVEs
observed exploitation
nono source reports it
In the Linux kernel, the following vulnerability has been resolved:
io_uring/memmap: cast nr_pages to size_t before shifting
If the allocated size exceeds UINT_MAX, then it's necessary to cast
the mr->nr_pages value to size_t to prevent it from overflowing. In
practice this isn't much of a concern as the required memory size will
have been validated upfront, and accounted to the user. And > 4GB sizes
will be necessary to make the lack of a cast a problem, which greatly
exceeds normal user locked_vm settings that are generally in the kb to
mb range. However, if root is used, then accounting isn't done, and
then it's possible to hit this issue.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Affected products
Linux · LinuxRelated CVEs — Linux
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